Belt joint



W. S. HOWE BELT JOINT May 22, 1934.

Filed Aug.v 21, 1930 IIIIIIIJIIII Patented May 22, 1934 UNETED STATES PATENT' OFFICE Production Machine Company,

Mass, a corporation of Massachusetts Application August 21, 1930, Serial No. 476,884

3 Claims.

of positioning the joint in oblique relation to the path of movement of the belt instead of at right angles thereto. This construction obviates the tendency of the belt to crack at the joint and to jump as it passes the work, which faults have been experienced with the constructions of the prior art.

Another feature of the invention consists of the construction which leaves no ends or points on the abrasive surface of the belt which might 2O become loose and interfere with the operation of the belt. Such a construction makes it possible to reverse the direction of movement of the belt without danger to the belt or the work.

Other features of the invention consist of the construction, combinations and arrangements of parts hereinafter described and claimed, the advantages of which will be obvious to those skilled in the art from the following description.

In the drawing, illustrating two alternative forms of the invention, Fig. 1 is a plan view illustrating the belt ends out of engagement; Fig. 2 is a plan view showing the belt ends in engagement; Figs. 3 and 4 are plan views illustrating the alternative form of the invention; Fig. 5 is a sectional elevation taken on the line 5-5 of Fig.

2, and Fig. 6 is a sectional elevation taken on the line 6-6 of Fig. 4.

Abrasive belts comprise in general a body portion of firmly woven canvas or other fabric or rubber upon one side of which a surface coating of emery or other abrasive is adhesively secured. The end portions of the abrasive belt are joined to form an endless belt arranged to travel over pulleys in a well-known manner in grinding or polishing machines, the back or smooth surface of the belt coming in contact with the pulley and the abrasive surface being positioned to engage the work being ground or polished. When the edges of the abrasive, complementary in shape, are brought together into intimate juxtaposition, such a joint is called a flush joint.

Referring to Figures 1 and 2 of the drawing, the end portions of the belt are indicated at 6 and 8, and consist of one or more ply of canvas ss-coated with abrasive. 10, 12 and 14 are nonabrasive portions or surfaces from which the abrasive has been removed by skiving or grinding in order to adapt said surfaces to underlie the opposite belt end and be adhesively secured thereto. (See Fig. 2.)

An important feature of the invention is the V-shaped construction of the joint whereby the joint enters the work in a shearing manner, thereby preventing the tendency of the belt to jump, which is one of the disadvantages of the 5 constructions in the prior art. This construction also prevents cracking of the belt along the line of the joint.

In skiving or removing the abrasive from the surfaces 10, 12 and 14, care should be taken that only the abrasive material is removed leaving the fabric uninjured. Glue or cement or other material may now be applied to surfaces 10, 12 and 14 and the belt ends adhesively secured in the position illustrated in Fig. 2, the non-abrasive surface 14 underlying the abrasive surface 6, and the non-abrasive surfaces 10 and 12 underlying the abrasive surface 8. In this position the cemented surfaces are pressed together to form a joint of substantially the same thickness as the belt.

A feature of the invention is the construction of the joint which leaves no ends or points of the belt on the abrasive side thereof which might become loosened by contact with the work and interfere with the proper operation of the belt. 35 To this end the points 16, 18 and 20 of the abrasive surface are positioned short of the points 22,

2 4 and 26 of the non-abrasive surfaces or portions 14, 10 and 12 respectively, which portions or surfaces underlie corresponding portions of the opposite ends of the belt and eifectively prevent the said points on the abrasive side from lifting or otherwise getting out of alignment.

Figs. 3, 4 and 6 illustrate an alternative form of the invention in which the point 23 of the nonabrasive portion 15 is passed through a slit 28, the portion 15 underlying the abrasive surface 6, as in the former construction, and the non-abrasive surfaces 10 and 12 underlying the abrasive surface 8 as in the former construction, the only difference being that the surfaces 10 and 12, as here illustrated, are united or continuous, giving double support adjacent the point 23, whereas in the former construction they are separated to permit the non-abrasive surface 14 to pass between them.

While the invention has been illustrated and described in its preferred form, it is to be understood that it may be embodied in other forms Within the scope of the following claims:

1. A flush joint for abrasive belts comprising two belt ends having abrasive surfaces brought into endwise juxtaposition each of said ends having a non-abrasive portion underlying the abrasive surface of the opposite end and secured thereto, one of said non-abrasive portions passing through a slit in the opposite end,

2. A flush joint for'abrasive belts comprising a belt end in the form of an acute angle adapted to be brought into juxtaposition with a belt end in the form of a complementary re-entrant angle to form a joint in the shape of a letter V with a continuous abrasive surface, the end in the form of the re-entrant angle having a continuous nonabrasive surface extending therefrom, and the end in the form of the acute angle having nonabrasive surfaces at the apex of said angle, the non-abrasive surfaces underlying the opposite ends of the belt and the apex of the acute angle passing through a slit in the opposite belt end.

3- A flus J n f r as be c mp is ns belt section having an abrasive surface, the end of the surface being in the shape of a salient angle, a second belt section having an abrasive surface the end of the surface being in the shape of a complementary reentrant angle, the sections being brought into juxtaposition to form a continuous, uninterrupted abrasive surface, the first mentioned end section having a tongue of relatively narrow width transversely of the belt and extending from the apex portion of the salient angle and with a non-abrasive upper surface to underlie the second end section adjacent the apex of the reentrant angle, and the section with the reentrant angle being provided with portions extending from the sides of the reentrant angle and of a width transversely of the belt several times that of the tongue and having a non-abrasive upper surface to underlie the side portions of the salient angle section, the underlying portions of each section being secured to the under side of the other section.

WILLIAM S. HOWE, 

